Jet aircraft, such as commercial passenger and military aircraft, utilize thrust reversers on the aircraft's jet engines to reduce the aircraft's speed after landing. One type of thrust reverser used in modern jet aircraft is the cascade type, which is described in more detail in U.S. Pat. No. 5,448,884, which is hereby incorporated by reference as if fully set forth herein.
Referring to FIG. 1, a conventional aircraft nacelle is indicated by reference numeral 18. The nacelle 18 shrouds a jet engine 20, which is supported on a strut or pylon 22 that is coupled to a wing 24 (only a portion of which is shown). The nacelle 18 includes a nose cowl 26, a fan cowl 27, a thrust reverser sleeve 28, a core cowl 30 and a nozzle exhaust 32. Although several of these components are made up of two mirror-image sub-components that are split vertically in a clamshell arrangement, each component will be referred to herein as being one piece.
As shown in more detail in FIGS. 2 and 3, the thrust reverser system 34 includes an inner duct or fan duct cowl 36 and an outer sleeve 38. The outer sleeve 38 translates in an aft direction as identified by arrow 42 and a forward direction indicated by arrow 44. When the thrust reverser is deployed, the translating sleeve 38 moves aft from a stowed position shown in FIG. 1 to a deployed position shown in FIG. 2. In this process, cascade vanes 46 mounted to the thrust reverser support structure are uncovered. The cascade vanes 46 are slanted in a forward direction so that during the operation of the thrust reverser system 34, fan air (designated by arrow 47) from the engine fan is re-directed forward through the cascade vanes 46 to aid in decelerating the aircraft.
Air driven aft by the engine fan flows along an annular duct 48 that is formed between the fun duct cowl 36 and the core duct cowl 30. Movement of the sleeve 38 in the aft direction causes blocker doors 50 to pivot from their stowed positions (FIG. 3) to their deployed positions (FIG. 2) where the blocker doors 50 are positioned to block rearward movement of the air from the engine fan through the duct 48. In this manner, all rearward movement of the air from the engine fan is re-directed forward through the cascade vanes 46.
One drawback of the above-referenced thrust reverser system 34 is that such systems are integrated into both the nacelle and the bypass structure. Accordingly, any engine movement will effect the external nacelle flow lines.